1. Field of the Invention
The present invention relates to a light guiding strip, and more particularly to a light guiding strip applied in a backlight module of a display (usually a computer display and a television, hereinafter referred to as the display).
2. Description of the Prior Art
Backlight modules are basic components in liquid crystal displays. Currently, many types of backlight modules are used. For example, in a conventional side-lit backlight module, LEDs are disposed on both sides of the backlight module, and a light guide is provided in the display area of the LCD display, and thus the light emitted by the LEDs at two ends of the backlight module can be uniformly irradiated out of the backlight module via the light guide. In a direct-lit backlight module, a plurality of LEDs is provided in the display area of the LCD display directly, so the light guide is not required. However, the half-power angle of the radiation of each LED is about±60 degrees. Therefore, in the direct-lit backlight module, a distance must be kept above the LEDs so as to allow the light emitted by two neighboring LEDs to be partially overlapping. The above two types of backlight modules have advantages and disadvantages, respectively. The side-lit backlight module employing the light guide is usually heavier than the direct-lit backlight module; however, the LEDs in the side-lit backlight module are arranged less densely than those in the direct-lit backlight module. Due to its long light-mixing distance, the direct-lit backlight module is relatively thick and also requires an additional circuit board. Therefore, the cost of the overall structure of the direct-lit backlight module is higher.
US Patent Publication Nos. 2005/0007758A1, 2005/0140848A1 and U.S. Pat. No. 6,966,664 provide backlight modules with increased LED pitch. Firstly, US Patent Publication No. 2005/0007758A1 provides a strip-shaped light guide with a plurality of openings, and an LED is disposed at two ends of the light guiding strip respectively. When the LEDs emit light, a plurality of openings of the light guide will radiate light to simulate a plurality of LEDs. Further, US Patent Publication No. 2005/0140848A1 provides a backlight module with a plurality of strip-shaped light guides, which is advantageous in that the brightness of the backlight module can be adjusted by individually driving the selected light guide. Moreover, U.S. Pat. No. 6,966,664 provides a light guiding strip, in which the light emitted by LEDs at two ends of the light guiding strip is concentratedly irradiated out from an arced surface of the light guiding strip, so as to form a linear and uniform light source.
In view of the above, the light guiding strip of the conventional art and the backlight module and display using the light guiding strip have the shortcomings of being thick and heavy or having a high cost, so it is necessary to provide a light, thin, and low-cost light guiding strip and a backlight module and display using the light guiding strip.